I can see why a (particular) human face is beautiful (sexual attraction) or the face of a young animal (e.g. large eyes reminiscent of a human baby). But why is a rainbow beautiful? And why is my firefly screensaver beautiful? Why does some abstract art (no natural form) draw one to tears? Some music (without voice/words) is like this (think Rachmaninoff's Rhapsody On A Theme By Paganini); why?

.... because embedded within contains all frequencies in a certain visual harmonic combination with the capabilities of exciting vision. A dash of red, with a pinch or orange, a ... of green, etc. etc.

.... because embedded within contains all frequencies in a certain visual harmonic combination with the capabilities of exciting vision. A dash of red, with a pinch or orange, a ... of green, etc. etc.

It's funny you should say that .. Some years ago I was in a discussion with my research group about using multiple electric field frequencies applied simultaneously to microelectrodes for the purposes of dielectrophoresis of biological cells. At that time no-one had used multiple frequencies. We discussed the possible polarization mechanisms that would be induced and how these might interact, and the effect of this on cell collection upon electrodes. There are a range of polarization mechanisms available and (dependent upon the frequencies selected) when multiple frequencies are applied, several mechanisms would be induced at the same time. It was not simply that the multiple frequencies would provide a different waveform, but that different mechanisms would come into play simultaneously. I can see something related to this possibly being applicable to the present problem, i.e. that different (sensory/cognitive mechanisms) might come into play simultaneously to provide a response that in some way is recognized as significant (another sort of quale), experienced as beauty. But a single (isolated) stimulus might do the same thing?

@Hey Hey: The Brits do indeed spell things inefficiently like colour. But its Queens English, and you'll damn well respect it! A colleague at work was talking to a yank on the phone (apologies if that is derogatory, I don't believe it is), and she asked him to slow down because of his accent... He replied "No, luv, its YOU that has the accent!"